One of the main problems when a wireless transmit/receive unit (WTRU) is receiving multimedia broadcast multicast services (MBMS) is maintaining the service continuity and minimizing the delay during handover and cell reselection. Furthermore, the service continuity must be maintained and the delay must be minimized when the WTRU moves across from a multimedia broadcast single frequency network (MBSFN) service area to a non-MBSFN service area, but within the same MBMS service area.
Different steps that need to be considered when an idle mode WTRU receiving an MBMS transmission in an MBSFN service area approaches the border of the MBSFN service area, have been raised. The steps include: 1) detect that the WTRU is approaching the border of the MBSFN service area; 2) move to active mode; and 3) request the reception of the MBMS service in single cell mode point-to-point (PTP). The target cell evolved Node-B (eNodeB) also has to check whether the requested service is available or not and, if not, 4) join the multicast distribution tree for the MBMS service; and 5) finally start providing MBMS data to the WTRU in single cell mode.
While a few high level system solutions have been suggested, a more integrated solution that would help minimize delay and maintain the service continuity is needed. Accordingly, it is desirable to enhance the transit from a non-MBSFN area to another non-MBSFN service area or to an MBSFN service area, as well as reselection from an MBSFN service area to a non-MBSFN service area.